Mexico Air Pollution Intensities

This database provides estimates for the amount of pollution (load) produced from a unit of production (in this case, indicated by employment) by specific industry sectors and by firms within particular size categories. The pollution intensities are for the following pollutants:
particulates (PT);
sulphur oxide (SOX);
carbon monoxide (CO);
nitrogen oxide (NOX);
hydrocarbons (HC).
This dataset has been produced by DECRG-IE of the World Bank in collaboration with Mexico’s Instituto Nacional de Ecologia (INE), using a database they provided, the Sistema Nacional de Informacion de Fuentes Fijas.
The units of measurement for employment intensities are tons per employee. The pollution intensities are at 2 and 3-digit ISIC (version 2) levels. Additional datasets were calculated for firms of various size (small, medium, large). Small firms are defined as having employment at twenty or less. Medium firms are defined as having employment between 21 and 100. Large firms have employment over 100. The sample size for intensities by firm size was:
small firms 2,346,
medium firms 2,143,
large firms 1,310.
Preliminary analysis of results revealed an outlier problem. Therefore, the top twenty-five polluters were deleted from the overall dataset, and the top ten polluters from each plant-size category were removed, before calculation of pollution intensities.
This dataset was revised on 11/17/97. The 2 and 3 digit results were changed to make them consistent with the results for the size categories by removing the top 10 polluters from each category. Please make sure that you are using data marked 11/17/97.